ar X iv : a st ro - p h / 05 02 31 5 v 2 1 8 Fe b 20 05 GEOTAIL observation of the SGR 1806 - 20 Giant Flare : The first 600 ms
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چکیده
On December 27, 2004, plasma particle detectors on the GEOTAIL spacecraft detected an extremely strong signal of hard X-ray photons from the giant flare of SGR1806-20, a magnetar candidate. While practically all gamma-ray detectors on any satellites were saturated during the first ∼500 ms interval after the onset, one of the particle detectors on GEOTAIL was not saturated and provided unique measurements of the hard X-ray intensity and the profile for the first 600 ms interval with 5.48 ms time resolution. After ∼50 ms from the initial rapid onset, the peak photon flux (integrated above∼50 keV) reached the order of 10 photons seccm. Assuming a blackbody spectrum with kT =175 keV, we estimate the peak energy flux to be 21 erg seccm and the fluence (for 0-600 ms) to be 2.4 erg cm. The implied energy release comparable to the magnetic energy stored in a magnetar (∼ 10 erg) suggests an extremely efficient energy release mechanism.
منابع مشابه
ar X iv : a st ro - p h / 05 02 31 5 v 1 1 6 Fe b 20 05 GEOTAIL observation of the SGR 1806 - 20 Giant Flare : The first 600 ms
On December 27, 2004, plasma particle detectors on the GEOTAIL spacecraft detected an extremely strong signal of hard X-ray photons from the giant flare of SGR1806-20, a magnetar candidate. While practically all gamma-ray detectors on any satellites were saturated during the first ∼500 ms interval after the onset, one of the particle detectors on GEOTAIL was not saturated and provided unique me...
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